U.S. Pat. No. 4,108,882 shows a method of preparing siloxanes by reacting chlorosilanes with methanol in the presence of quaternary ammonium catalysts. The virtue of this process is that in one step one can go from a chlorosilane to a siloxane and produce methylchloride which is a useful intermediate in the preparation of methylsiloxanes. Also, the process has the virtue of producing very little dimethylether. The primary object of this patent was to produce high yields of cyclic diorganosiloxanes. Therefore, the patent is limited to either diorganochlorosilanes or triorganochlorosilanes and there is no teaching therein of the incorporation of any monoorganotrichlorosilane in the starting materials. One might expect that the incorporation of monoorganotrichlorosilanes in the reaction mixture would cause gellation and would thereby reduce the formation of the desired cyclics and produce an inefficient process. The latter is particularly true since the formation of gels in the reactor would interfere with the activity of the catalyst.
Fluids containing monoorganosiloxanes are desirable for many applications. For example, the incorporation of 3 to 4 mol percent monomethylsiloxane in a fluid containing dimethylsiloxane reduces the glass transition temperature from approximately -40.degree. C. to -100.degree. C. There are many applications in which such low temperature stability is required. Furthermore, the incorporation of significant amounts of monomethylsiloxane in a diorganosiloxane fluid increases the specific gravity. In some applications, particularly in the electrical area, it is desirable to have a diorganopolysiloxane fluid with a specific gravity above 1 so that water will float to the top of the fluid. This makes the water much more easily removed from the system.
It is the object of this invention to produce monoorgano containing polysiloxane fluids by a method which gives excellent yields of such fluids essentially free of gels. It is also the object to carry out the procedure by a manner which produces methylchloride containing small amounts of dimethyl ether.